The term tumor refers to abnormal masses of new tissue growth which is discordant with the economy of the tissue of origin or the host's body as a whole. Tumors are common in a variety of mammals and the prevention, control of the growth and regression of tumors in mammals is important to man.
Tumors inflict mammals and man with a variety of disorders and conditions including various forms of cancer and resultant cancerous cachexia. Cancerous cachexia refers to the symptomatic discomfort that accompanies the infliction of a mammal with a tumor. These symptoms include weakened condition of the inflicted mammal as evidenced by, for example, weight loss. The seriousness of cancer is well known, e.g., cancer is second only to heart and vascular diseases as a cause of death in man.
Considerable research and resources have been devoted to oncology and antitumor measures including chemotherapy. While certain methods and chemical compositions have been developed which aid in inhibiting, remitting or controlling the growth of tumors new methods and antitumor chemical compositions are needed.
U.S. Pat. Nos. 4,162,308 and 4,162,309 to Calvin and Ellis describe that water soluble extract from marine red alga have been found to be effective to inhibit the growth of certain herpes viruses.
U.S. Pat. No. 4,162,308 describes water soluble extracts from marine red alga selected from a group consisting of Turnella mertensiana, Schizymenia epiphytica, Turnerella pennyi algae and mixtures thereof as effective to inhibit the growth of herpes simplex virus, type 1 and type 2, and herpes zoster, and to relieve the pain caused by infection attributable to such viruses.
U.S. Pat. No. 4,162,309 describes the use of water soluble extracts from marine red alga selected from a group consisting of Neodilsea americana and Neodilsea integra algae and mixtures thereof to inhibit the growth of herpes simplex virus, type 1 and type 2, herpes zoster, and to relieve the pain caused by infection attributable to such viruses
In addition to the water soluble red alga extracts described in the above noted U.S. patent applications to Calvin and Ellis other compounds have been isolated from red alga and marine organisms known as sea hares which are mollusks which diet on red algae. These compounds include halogenated chamigrenes and have been described in various literature references including P. J. Scheuer, Ed. Marine Natural Products Volume 1 (Martin), 1978 and Volume 5 (Erickson), 1983 Academic Press, the entire disclosure of this reference is hereby incorporated herein by reference.
Co-pending applications of the present inventors relate to red alga and sea hare extracts and derivatives thereof comprising certain chamigrenes which show antiviral activity and certain cyclohexadienones which show antiviral and antitumor activity i.e., U S. patent applicant Ser. Nos. 682,896; 682,278, now abandoned, and 744,620, respectively. The entire disclosures of these three patent applications are hereby incorporated herein by reference.
In an article entitled "Structures of Halogenated Chamigrene Derivatives, Minor Constituents From the Red Alga Laurencia nipponica Yamada" appearing at Bull Chem Soc Jpn., 56 (no. 12) at Pp 3824-3826, (1983); the authors, Minoru Suzuki, Makoto Segawa, Teruaki Suzuki, and Etsuro Kurosawa of the Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060, Japan, disclose various compounds derived from red alga Laurencia nipponica. These compounds include halogenated chamigrenes and methods of their isolation and preparation. No disclosure has been made by Suzuki et al. of the bioacctivity of these compounds. The entire disclosure of the Suzuki et al article is incorporated herein by reference.
One of the compounds prepared by Suzuki et al and disclosed in the above-mentioned article having the structure: ##STR1## was supplied by Suzuki et al and examined by the present inventors, along with other halogenated chamigrene compounds, for biological activity.
It has now been found that certain chamigrene extracts from marine organisms such as red alga and sea hares which diet upon red alga, possess useful biological activity.